1. Field of the Invention
The present invention relates to an image processing apparatus for making a document whose originality can be certified.
2. Description of the Related Art
In order to certify the originality of a document such as a public document, soft thin paper is used or a tint block or watermark is formed on a document. It is thereby possible to clearly discriminate an original document from a copied document.
However, in the case of a document consisting of a large number of recording sheets, the use of soft thin paper is costly. Further, in the case of a document with a tint block or watermark formed thereon, repeated copying of the document, such as further copying of a copied document, makes the tint block or the watermark not recognizable, thereby preventing the copied document from being discriminated from the original document.
With such being the case, an image processing apparatus is described in Japanese Patent Laid-Open No. 2003-1905, which applies mechanical processing to a document so as to certify its originality. In this image processing apparatus, through holes arranged in a predetermined order are formed on printed recording sheets. It is possible to recognize at first sight a difference between the original document, on which the through holes are formed as thus described, and a copied document.
It is possible to certify the originality of a document with through holes formed thereon as described above. However, in a document consisting of a large number of recording sheets, if a recording sheet has been taken out and missing, or the order of pages has been changed, such defects cannot be found since each recording sheet has a through hole. Therefore, this document is incomplete as a document and incapable of certifying its originality with reliability.